Edward g



B. G. HEWITT.

FURNACE.

(No Model.)

UNITED STATES PATENT OFFICE.

ED\VARD G. HE\VITT, OF BROOKLYN, NE\V YORK.

FURNACE.

SPECIFICATIONfm-ming part of Letters Patent No. 345,971, dated July 20,less.

A'pplication filed November 28, 1885. Serial No. 184.194. (No model.)

To all whom, it may concern.-

Beit known that I, EDWARD G. HEWITT, a citizen of the United States,residing at Brooklyn, in the county of Kings and State of New York, haveinvented certain new and useful Improvements in Furnaces, of which thefollowing is a specification, reference being had to the drawingsaccompanying and forming a part of the same.

My invention is an improvement in appliances for introducing heated airinto furnaces above the fire or coals, in order to effect amore perfectcombustion of the gases and solid particleswhich would otherwise passoff incompletely consumed through the lack of a sufiicient supply ofoxygen.

The objects of my invention are to produce not only a cheap and yeteffective means for accomplishing this, but also one that may bedirectly applied to any existing furnace of ordinary constructionwithout modification in any essential particulars of the latter.

In carrying out my invention I apply to the interior of the furnaceabove the grate and around the sides or walls of the furnace a tier offire-bricks constructed or applied to the walls in such a way as toleave air-passage between the furnace-wall and the bricks. Upon thesebricks I then build another tier of bricks or theirhercinafter-described equivalents, formed or applied in such manner asto continue the air-passages for some distance above the lower tier, andto afford outlets for the air through narrow slots or slits. Thelowertier of fire-brick extends somewhat above the fire or bed of coals, sothat the air which passes up behind or through the bricks enters theflame well up above the coal, while the fire does not clog up nor fallthrough the slots 'or narrow air passages. This is the general principleof the construction of the devices forming the subject of my invention.

In other respects the invention involves certain novel features in theconstruction and composition of the described devices, which are these:The bricks of the lower tier are of the refractory material commonlyemployed for firebrick. I prefer to mold them, however, with flangesthat extend from the lower edge nearly to the upper edge, and which restagainst the furnacc walls when the bricks are in place. ly this meansthe bricks may be made comparatively thin without impairing theirstrength, so that the air behind them is more perfectly heated and abetter and larger airspace is formed. The upper tier may be made ofmolded firc brick, but as it is not in direct contact with the coals itis not neces saril y made of such refractory material. I thereforesecure greater cheapness and durability by using, instead of Iirebrick,cast-iron plates, and these I make with flanges that extend outward intothe furnace, and along the lower edge is also a flange or equivalent bywhich they are more securely held upon the fire bricks. The upper edgesof the flanges and plates are beveled off and rest against thefurnace-wall. This arrangement in its preferred form is illustrated inthe accom mnying drawings.

Figure l is a sectional view of a, furnace to which my invention isapplied. Fig. 2 is a partial section of the same on line a w of Fig. 1.Fig. 3 is a. similar section in line a 3/ of Fig.1. Fig. 4 is aperspective view of a modiiication.

A designates any kind offurnace, of which B B are the grate-bars.Immediately above these bars and along the furnacc'wall are laid theflanged bricks C C. As I have before stated, these may be of anyconformation that affords free passage for the air up through them, andit is obvious that they may bemold ed in vertical or horizontal sectionswithout at all departing from the invention.

In the present case the bricks consist of the slabs O (J with flanges D,that extend from the bottom nearly to the top of the brick, and they areplaced with these flanges against the furnace-wall. The upper tier ofiron plates, E, are laid with their lower edges resting on the tops ofthe fire-bricks G, and their up per edges resting against thefurnace-wall. They are placed a little distance apart, whereby the longnarrow slots or openings F are formed. I prefer to make these plateswith lower flanges or lugs, G, that abut against the inner faces of thefire-bricks and hold both bricks and plates in position. I also makethem with side flanges, H, for the purpose hereinafter described. Ifthis appliance is to be used in a circular furnace, the bricks andplates should be slightly rounded to conform to the shape of the same.In a square or rectangular furnace the corners are built up with thebricks described, and any convenient form of angle-plate is used.Thedevice may be used entirely around the furnace or only on two orthree sides.

The operation or effect of this combination is as follows: hen the fireis started, two causes operate to draw up the air from below the grateinto the space in the furnace above the fire-the natural draft in theflues and the expansion of the air behind the bricks and plates by theheat of the fire. The heat to which these are exposed raises the airthat passes behind them to a veryhigh temperature. This is the bettereffected by employing the flanges II, between which the air passes in athin film. The air issues then into the flame not in jets,

as would be the case if small perforations only were made in the plates,but in thin and extended films, by which means a much more perfecteommingling of the oxygen with the flaming gases is effected and a moreperfect combustion obtained.

I am well aware that a great variety of means have heretofore beenemployed for in troducing healed air into a furnace above the grate, andI do not claim this, broadly. The device which I have invented anddescribed herein offers, however, these several advantages. It isextremely simple and easily applied to any kind of furnace. It furnishesa plentiful supply of hot air by natural draft alone, and withoutrequiring any complicated and elaborate means for heating the air andforcing it into the furnace. These and other advantages are due to thenovel features in the construction which Ihave above described.

Vhat I claim is- 1. The combination, with a furnace, ofalining providedwith or forming air-passages extending from the ash-pit and openingintothe furnace above the fire, the said lining being built up upon thegrate-bars of a number of sections of a refractory material,and providedwith long narrow openings for the entrance of air into the flame, as setforth.

2. The combination, in a furnace,of a tier of fire-bricks laid above thegrate-bars and formed or applied so as to form air-passages, and a tieror series of east-iron plates laid upon the bricks, the two tiers orseries of bricks and plates forming a lining for the furnace, the upperportion of which is formed or provided with openings or outlets for theheated air to issue into the flame, as set forth.

3. The combination, in a furnaee,of a tier of fire-bricks laid above thegrate-bars and formed or applied so as to form air-passages, and a tieror series of refractory plates laid upon the bricks and with their upperedges resting against the furnace-wall, the said plates being placed atshort distances apart, so as to leave long narrow outlets for the heatedair to issue into the flame, as set forth.

4. The combination, in afurnace,of atier or series of fire-bricks laidabove the grate-bars and formed or applied so as to leave air-passages,and a tier or series of east-iron plates laid upon the fire-bricks withtheir upper edges against the furnace-wall and at short distances apart,so as to leave long narrow outlets for the heated air to issue into theflame, as set forth.

5. In a furnace, the combination of a tierof flanged fire-bricks laidabove the grate-bars with their flanges against the furnace-wall, so asto form air-passages behind the bricks, and a series of iron plates laidabove'the bricks with their upper edges against the furnacewall, andprovided with outlets for the air to issue from the passage into theflame, as set forth.

G. In a furnace, the combination of a series or tier offlanged firebrick laid upon the gratebars with their flanges against the furnacewall anda series of flanged iron plates above the fire-bricks, theirupper edge beveled and resting against the furnacewall, the plates beingplaced at short distances apart, so as to leave openings for the heatedair to issue into the flame, as herein set forth.

7. In a furnace, the combination of a series or tier of fire-bricksformed with flanges on their inner faces that extend nearly to the upper edges of the bricks, and a tier of cast-iron plates having flangesor lugs along their lower edges adapted to fit over the edges of thefire bricks, the plates being laid with their upper edges against thefurnace-wall and at short distances apart, to leave outlets for theairpassages behind or in the bricks, as set forth.

EDWARD e. HEWITT.

Witnesses:

PARKER W. PAGE, J AS. DANIEL (JoMr'roN.

